Dr. Sudmeier proposes research which can contribute to a greater understanding of the structure and function of zinc metalloenzymes. The primary method proposed is direct observation of selected single atom nmr signals (primarily 1H, 13C, 113Cd, 199Hg and 15N), taking advantage of the high sensitivity and versatility now available in a state-of-the-art, large-tube multinuclear FTNMR spectrometer. He proposes to explore the usefulness of 113Cd nmr in 113Cd-substituted Zn enzymes (such as carbonic anhydrases) as a probe for structure and binding of enzyme ligands and inhibitors in the active site. Chemical shifts, nuclear relaxation times, and spin-coupling caused by binding of 13C- or 15N-enriched inhibitors will be among the primary diagnostic tools. He will also explore the utility of 199Hg nmr in protein complexes, both for the use of 199Hg as an active site replacement for Zn, and for the determination of mercury binding sites in X-ray crystallographic, toxicological, and environmental studies.